Telephone exchange system.



T. e, Mmm. TELEPHONE EXCHANGE SYSTEM. y Armcmou mtu 1AN.12.1Jos. nrufwen 9.25.191?. l g 1,282,957. Patented on 22,1918;y

4 SHEETS-SHEET l.

)zzz y A T. Gr MARTN.

TELEPHONE EXCHANGE SYSTEM. APPLCATION FILED IAN. i2. 1905. RENEWED FIB Patented Oct 4 SHEETS-SHEET 4.

nois, lii'ii'c. invented a certain new and usei I i UNITED STATES PATENT OFFICE.

TALVBOT G. HARTN, 0F CHICAGO. ILLINOIS, ASSIGNO-R. BY MESNE ASSIGNMENTS, TO i 'Aumoiunc ELEcTnIc COMPANY. A conronA'rIoNoF ILLINoIs.

TELEPHUNE EXCHANGE SYSTEM.

.1 282257 Bpe'citcgtion of Letters Patent. Patented ct. 22, 1918.

Application med .Tamihrym 1906, Serial No. 295,753. Renewed February 25. 191.8. Serial No. 219,158.

my invention consists in matters hereinaf teiset forth and claimed.

Figures 1 and .2 illustrate eliagranunat-ieall'y the ineane` employed by a subscriber offan automatic cominon battery exchan e in calling* a suliscriber of an automatic 'ocal battery exehange. The two exchanges arc connected by triink-lineiI one of whichA is To, l whom it may concern Be it known thall, T ALmrr (l. Malerin', n citfzii of `the United States of America,V j and iegfzident of (f liicago, (.ook county-` 1llful. Ilifipioveineiit in Telephone-Exohango Svisti-nik, of whieh the following is a specification.

My linvention relates to tele )lione systems shown terminating at one end'in the repeater in geii'eal, lint nniijeliarticu iii-ly to anto- R at the calling central station and at the matic or seniifautiainitie teleplioinsystems, iindfefaneiiillly. to. aiitoiinitie telcplioilni oxclumge animatie. ifytliat ina'tis'uhn char noter iuwliieh, sube'eribei'eontrolled trunk selecting. andi]ne-conneiting switching niacliine'i-ysr eiiifilo'yed, the expedient. for ena'blingf. the su' acrilici-.8. to control they said iinichii'ifery;` oonsiiiting o fsuhscij'ilxfra 1inpulso trailsiiiitters or calli ng. de v-ice s` so constructed that: any. calling subsriber can transni'it the. electrical.; n 4nece,ssary forealliiigytlienumberA of iiny otherl subi other end in the second-selector S at the ea'lled ventral station.

Fig. lsliows the common battery sub-sta tion #7000 and'first-selector I"l allotted t0 saidsub-station and the repeater R.

Fig'.V 2 shows the second-selector S and a connector connected witht'lie line. leading to the sub-stat-ioii #24:20. bridged across whil'h line af tiret-selector lf2 will be recognized; which belongs. exelusji'ely to the line #24720.

Figrf is a diagram 0f a first-,Selector Fig. fl' is a diagram of, ir connector.

The sul )"-.-statio1`i`s en iployed inxconneetion with the con'iinon battery exehange in question are' a`fl`-l`"of af` welbknowii' and' Suitable type.V Subestation #7000. for instanemis 'at mee ieeogiiized by the peculiar switch-hook stateill.- they-object, of-'iiiy invenn bf urn improved. and .Y f 1-lfi'jijiiiosysteiui`4 L its my intention are the provision o an. improved repeater for use in es tiibl Ling. 'ii talking circuit between a 2 which' islandewith" a number of cani-like 3i)` V'rsu-bise .of `4one exchange and the sub .arnis31 4'.- i'i "i`i'i'id 6i." The pru'nary 'circuit at serihe ainitheri exchange; the provision said station when `in'iise leA bridged' nei-oss the niaiii' line and comprises` in series the primary winding'. Tof. thc ncluetioncoil ytl. la tifansmitter 9'; a eoi'ifplcj of Springs' 10 and 11` identified with. the signali and two .springs 15-`nnd""`144 means `of which the said circuit is iiinintiiinedj closed or' opened (lepefinl fig uponiivhetf er the hook is: itl-i or dow-ii."4 Si'id'hool ils* he l pivoted' by oncerid o 'the serew` 1fi',`a'udi foicedto H risewh'ei'ie'veif thej weightof the eeiver 16 is -i'ellnived floii'i it."by.a suitable switchvhook-Spring not shown4 The secondary cirtuit'i aliniljiiry'toftjhi primary. comprises the` said receiver i'n' Series with the. secondary windin` 17 )f" tliendutionreol Sein' a pdr- *nnmeiit y elosedfloeal eil-enit; The 'ringer circuit at siiidf'Sl'ibfsjtntioii 'includes the ringer switch liiuiltr'- is? down' is; clo'jsedjby thc cam he saidI ringing-circuitof ni'eime. iol? estahlhing a trunk-line connection between a. Subsei'ilxa of a common battery uiit'oniatio telephone, exchange and; it subscriber :of ai loca-rl a automatic telephone exchange the )i vision of an iin- `iroiedV const ru'tion alii-l` arrangement where- V illfng" '-uhseiihei o f-th common bat-.

` 'IQ 3X 'elallj pariitamf ir.eliailacte i".`

' In certiinire [it iny-presentinvention is inthe ,aint-urea() an iiiiliijoveinentfoii thel mha-hone exelan 5y-stein'dieeloaed' in .my -.i i\` einliiig...applications4 Serial Nos. 202,728 ainlztieldligl."

'EU the :foregoing and other useful ends,

55 frguneinil is,retgimedfemine e distinte' from un; materielle becnuse the saidsprings umlQO'spiing' apart after the cum-'arm is x'eniovet'l from the lspring 19; The czu-n`-a,rin5 controls thei continuity of :i ground eircuit between the sii-culled ground-,post 22 undl the-ground terminal G, by means of two springs 23 and that iii-'eE included in sui(l"eireut. l AThe 'i substation hus thre e ether springs 25 26 and 27 which ure'knoivn as the release- 10, springs and by means of which the main l1ne-e0nciuetors may be ygrounded silnultzi-- 'neously for the purpose ofrestoring ehe ex- Achange apparatus in a, manner that .w il1 be; fully expl'ained. Wheny the hook is (lepressed, -as it descends, the suid. xje 1e nse, springs :u e forced `together by the ez m arm 3, ivhirh lattelitlien ,engages ,the laterally 25, he. engaging portienspf the eem 3 -ancll `)rin ,25 are cenetruei'ed withJ theirfsurf l .g v., l

as the heck dewn. onesurfuee toi'I thev prejeetien Q8 l is engaged. by the calin-erin;-V anrwhen 1t rises tlie oppes ite surface lsinet.

0 eziehstreke yof the hoek the canhurin' or ,dlsengziges the spring 25. in'ipulse suitablelesigni The jie illustrated how? des by .mi spring l,

:Brde

, und thev the igiruting 1tilt 80 `is attracted, and'when the magnetization` ceases the retraetingf'spring90`restores said' `arn'latn're to its normalfposition; The upl `ward'movement of" the` armature' limited` "by the )ole-pieces of the magnet-'coils 88 and 89,` an` vthe lower limit is` marked by va section of the switeh-franiektlmt passes under the arm `01. Said arm. is`known as the vertl? `cal-arm and extends 'fowadly from the vertiealfarlnature @6,y of which latter f it is la part. The \'ertiealarm carriesy `onits end ay so-ealled lvertieall-lmwl 92' which. when the vertical#armature is .attraeteth engages" with somefonee the `circular teeth 00 to raise" the shaft. Nolli'lally the ander snrfaee yof the upper section' of Said -pawl` rests against a" p iecefthilt i "seeihl'ed tothe switeh-frame-` and thatiretail `hepawl' aw`ay` from ,the eirenhirI teeth `lvl'heii" ythe vertical#armature is` attnleted. a l e saidfpawl rist j, a `retraetxthrlist sf'th'e' nl'iward side of" t he] v` 'rentar teethi't. As soon as said" pajwl elea or'dvisen y igea its.-l\or|ln`l"li riitl'hy theft telthat t levertieal-armai dief-Pilares; thewertieal-piiwbv thefirea surface' of` its upper nipt piet ,orstoltivt'hieheonstio t itehfnlnfe. Therefdre, tx te` `pre,ventedr from` being than(in'notehy at a time by mo entnnl. It is eieai, then, that F9* not oiilYli raises the shaft, hat

tliait alsat'ts as a til-Ik" at the end of'eaeh strokegflhe r"tjerfie'alarm has also an liion" its'nnder edge that forks over@ uofenlhal release-link 051l of tiexible 'alt` Said link carries an aperfront end,` and isseeured toi ntfniatnreissaspendedfroni the frame by the s apports 9951.7 and ylsnormally retained l "by t'l js'pr ig` away fromr the [aile-liieee 45`of"t1he neleaseinnignet. A stop is suitably proriti'ed behind said a-rniattire t nam-menta* ien retraetedj The? fi ated andeonstruete( is :italie switt'l gli the pirots mi?.`

liohble-fdog` develops -lwhi'eh are s'ositti-iv y that the former mar eoihnfmite with `the t m'haft't rai. d andinhnornjnilrf *ion` and theflattet with the longiil t a ry,

Matinal ytletlis'itl" when `the shaft yis rotated:

t entries into releaalngof 'llo the ,night of the iifvots 102; the ljo'dfy` 0f G0,

the doiibleldognextent s rearwardly, andproL j .ting downthereffin is an `a'rnlml-` that. very prominent] during the switchai `Near t le extremity vfilitlier a normally` caught in the abertnre 9(if of the` releinsellinkll, and because of the aetion of the spring l0() through said link the dogs 103 and 104 areretainet'l; away from; the shaft; .=\lw`ays.4 at the yfirs-tt strokeof the .verticalarmatllre, the linkitl is"drawn'away `from dmlblef-"dog` is "rotated `bv the retraeting-y spring A1075 so thatI the dog'103 falls ander thetirst eirenlartootin and so that whenthe vertieala1rumt|ire returns to y its' normal [msition thesa'id shaft. is: retailled by said? dog in itsnew `position. The release-luik'itl, while t tbetdonbledogis free,rest`s with its freefend 4 upon'the lug 100. and ont of Ioekinl:"etwaigeyu ment therewith. When the i'ertiealmagnet is envi-giunta secondtime'the shaftis raised -a seemidstepandthe dog;y 103 at' the seeond fromr the shaft,` whieli latter being deptlved of its only s|lp1m|'t `tlien falliitoinormal posiikethe VertiiIatlmagLg onee raisedjit may` `rotated by a second operatingi;|1nrghet"`l085 known as, the mtarynnlipjnetiv Said magnet! hastwo eoils 109` and l` 1`0iztand unlike the' rert'ieal-lnagnet' has its 'armature `111` pivtfvt-edi in a vertical plane.

Saidy arnatnre mayr he moved'alkint a vertliealf axis that Tasses thronghmtlie ivots 112;,

Tite `limit oft 1e movement offsai "armature toxvalld'` the rotarwmagney' is determined by;

nient is ylirodmed hyrlhe rotarl-llila'glretfit-y 'lihe mot' noot the atnitaturel in theI 121s a; 'hlnnpinggj` post. as doesl` f v"nre'utnli At the endioftherlirstrotary ste iy the dog 104 falls behindthe first longitudivnali tooth` so that .when the rotary-pawl falls baul: theshaft is retained. It shouldloeelVi-iv dent that as the shaft is rotated thevertiealdog 103 is extrieated from, theglfoove below the? circular tooth with whichit hasbeenin nesting engagement, kby y,the passage of the y'rotary-dog. 104 over ythe Jlongitudinal tooth over which :it has to slide at the time; butat 'the beginning otA the i .tation itwill be evi- 410y dent that `the tooth which .has been caught l by the vertical-dog slidesionvto the shaft-rest StL/"and in ythis way the shaft yis still vheld iraised after the rotation begins. The rotary armature is provided `with aso-called inter-y '15 ruptersfinger 117 that separates Lthev inter '1 rupter-springs 118` `andI r119 whenever the ro- ^vtary-arn1ature is attracted, also with a ro- -tar v-armature-finger 120 Ithat exercises certain controlling influences ,over the armatureu 2Dk 121 of' the lasty oft thel operating magnetsy the private-magnet 122.

2'5 formed with a forwardly -projeetingrarm 124, the' Alatter having twotiat surfaeesin an -approxiin-.itely f horizontal plane.

mortgthe end of thesaid arnris .bent-l at ahiright angle downwardly and Acarries certain "i'neeha1nieal details, namely a lateralarin125 which 'is designed to control. eireuiits ,eoini Aprising the privatef'springs i126, 12T andjl'lSfr and a 'tootlreseapementf which ,includes two., -tl'exible springs 12.9and `130 each otwvhchy springsis riveted by -one end to the arrnl i 1124, one on the upper side and thc-other on "tli'eiower. i The upper. spring .is straightI and l hasfornied on-itsend two tootli-projfetions and-132 which extend downwardly, .while dotthelower one is bent-down andl atar-ight 'angle again to the front. *This double angle;

on the'lo\ver spring is` so designed that the latterniay elear or disengagethebentupor; tion 'of the private-arm, against. wlnehiporf 4E1 tionsaitl spring rests witha requisite degree,l

of tension. and so @that there inay be space in"-frontoffs:'1id bent-.portion ,toreoeive two:

"other tooth-shaped upward ['iroj eetin #pieces 'Y 133 and 134 that are lformed ont-het onward '50 end` yof said eseapenientsprn1g 129` andi: which are sustainedfin.luxtaposition, to the.V

- vupper teeth, but slightly to the rearthereof,

auxiliaryr` .switching mechanism Econ'nnon to f sut-h'. switelies. is fthe `so-ealled side-y leetor FWand comprises an arnr 13(` whieh is seured'to the switch-frame insueh a inan-l ner that itniay be iliade.d toswinggaliouta 'vertliital aXisithroughfthe.pivots 1317".; The

" `i`-i`glitiextren1ity of said anni is drawn out into artinger that worksl in eonjunetion with US5 the escapeinent-.teeth .f previouslyA described. .y

kSaid teeth, in anianner to be demonstratedv` `1 'edu`ee"tl`1e` outward niovenie'ntof the sidestep `niotion', which movement is produced by a retrzteti'ng'spring139. At the ibase of theitinger 138 a lult)r 1140 that'is bentto the front isfadaptedi to strikethe @ain-56 at a suitable t'i'ine. lVheneXer' the Ashaft .is Yrotated, however, said Cain is carried hf 1 vond lthe reaeli of saidhigg and the finger falls jate-ifl'liiatuie is drawn down' once and re- The said private- 'i armature 121" works ina vibratory mannerk about a' horizontal axis that passes throughl the supporting-points This armature isfy stored t'o itsfnorinal position. 'Thea-escape# downward stroke ofthe private-armature I 121,'lan`d fronibehind the 'latter tooth aty the fre'turn/ stroke. As soon as the eseapement- Further linger 'elears ordisengages theflattt-i'r` tooth rretractil)g-'spring 139 draws the' side- Ysivit'oli'to the, second position where it is stopped by the'lug 140 Ywhen 'it strikes the earn 56j Iinniiediately,then. when the ro- ,tary-i'nagnet energizes, the shafts rotated iand the eani passes out ofreaeh'of'the lug 140;A r,llientliefinger 133'ofneeessity falls againstthe tooth 134;. beeauseof-thef tension yiii the spring 139. rotation of the-shaft results when the rotary-armature 111- is at- .'trac'tetfl, by I"the vrotary-lnagnet, and' at the .saine tinie the rotary-armature-finger'-120 depresses .the private-armature- 121 andcauses theffinger 13S `to disengage from the-tooth `134 V and advance against :thel too'th 132. Then.l as the rotary-armatture' returnsto no1'- nial/ pgisition, ,when the rotary-magnet deenergizes the' private-arl nat ure," on vvtoll owing `.tliefinger 120,])ei'ixiits` the "escapenient-#inger .138 toeseape `from theflast.` tootl1"13:2, thus permitting the side-switel'iito passv to the Ithird position VAwith the savi'dfinger 138 rest- Aing".against the"sideswiteh-stop 146.

In their 'normal positions the 'sideisivi't cli-wipers t; :et-p@oints"147, 11S. 149' and 150,1espectively.: This position is knownr as the first position of the sideswitt'h. at which time, it will Abegelear. the linger 13S' is held behind the;eseapeinenbtooth133. In theseeond popers engage instead with eontactlpoints (15:1,y 15:2, 153 andr154, respectively; and

.when the said tingerwlSSiy falls?against the stop 1,46 tlieivipei's shift'thei'r positions and L?, inove Iinto =eontaet'with lcontact-points 155, @45611157 and 158x, respe'etively." vBe'ytn'feen the 141, 142,l 14.3 and 144 engage'wi'th the con- A lretracting-spring 135,I suitably loeatedi,

holdssaid armature normally away from the '-55jprivate-magnet pole-piece. A ,wellfknown spring 216, places the said trunk-releasefili" Fig. l many pm of thv lil-st lomo-link 121.39 is llmlvl` lllc vililotyol "oli vulothe c xtlvmihv of .i'hich tho rotaly-pawl 280 isloolzihwl Tllo., rotation ofther shaft is proff. lilood in Lllcfsnno stLp-by-step manner 10-,y sa'lfihl ihfnonnovtion 'with thv, ixst-svloctolgziuh (timo, that ilw rotynlji-mzlgnvt is ener- [115 the siglv-sn'tuli of 2945 side "gimll lw willing limA uiul plgufv across gllx'idlmi apparatus is rondom-l inthe upper tooth 132 :it about the time that the s lift-wipers are rotated onto the first contact of the seeoml level el their rcs-[motive bunks. s soon as `the energizing circuit through the i,'otaiy-iiigigiiet is i rotary-eromture then begins to normal position,- init?. the 1iri.viite-uriiiaure 121 as well, following,r up the receding',more nient of the roterl y-i1rniiiture-finger 120. Very soon the tooth 132 clears or disengiiges the eseepeirient-finger 1.38 also, and the sideswitcli sini-ings into its third position with the estanliieinent-inger 138 iigiiiiist the side- ,switch-A, i 14. Tlfie shiftinj ot the sidei switch,tulls"'iiu,ce inst kbeforethe interliliiiteitfng, j ti" prings 3118 and `119t time thu t th o y lo that has return to its gh the rotaryniitgiiet'has liecii openeil between the sideswitcli-wi per .141 undl the coi'itzict-point` 151,. When the motion of the roturrveiriiiature eeuses perniiinently, the operation of the first-selei'itor theiieon'ies to an end, the linewipers 53 aniil 54 h'iwing seized upon an idle trunk-line similar to the tii'unk-line Whose eoifiduct" 42]. and 422 teriiiiniite et the tentlitsetof eoi'itiu of the second level of the sume lineeliiiiik.` ilio seized line is 'irotected from further zure by ay guar ing potential teniporarilyv estiiiiilisheii at the privote-wiper, mnh therefore,` `:it the rsteontiiet ofi the si omi level of the priviitebank 51 end to ell other private-contaets iii multiple. Sfiii'l guarifling potential is established grouiuleiil ter private-c through the grouiuil termii 4Q, ooiiduetor 425, etor and the i should any use the n ling a guarding potential will. n appear ut the second privateeontmit of the 'second `level ofthe pri-I vatebenk 51, as wel] :is :it all other` private bamksinniul] 1- .A hoiild :i third first- ,i e t on the same ill:

e oon(v a v l well itsiuttheniiithv priv -c1 `)of i' the Second `level of` the .r Therefore, if thel first nine trim flint` ofthe f 'second leve-l orebu giiiird'ng pote 'al is found et each: he li st ninepriviite-` onteets `of 'o the privatebenkil. et the time nds his rothat the t 'li pressing button, 30,- 1 will not terminate ian k.

as soon 'en the w` have eut onto the first [termine] of the vel to .which theyfhave iiiterrlipted the i i iicr. describe-(1 )y reason of the eiiiiniiection, lictween the ,t

minal oit haittiiiry B1 `and said springs, and while ir also at -retuiiietl in engagement Withtlie s rings ret-Engage is attracted again, thefsh" priviite-contects the calling subrotairy side of the line until the carried beyond the last of `the busy truiik-liiicfi,..in this case onto the tenth tern'iiiial of the second level of the 'hunks in question. A place `in the following manner: Y giziiig circuit through the rotary-magnet being closed, as was pointed out, Vat the juneture when the side-switchwi er 141 engages with the contact-point 151, it Iierotaryfarmatui-eis attractedby` the rotaryfmagnetqlil,

of the shii ft will begin not to cease w1 pers lia ve been his .operation takes.

The enerps into second positionin the manner described; but then therotatlon and the shaftis rotated oiieistep, `in theme11- so i that the/line and" private w1 pers are ii'otiited into engagement with the first terminal of thesecond `level of theircre speetive banks.' Atkthe Sametime the private-armature is deprissed `by the.` rotary- :irmature-finger and the interriipter-springs 118 andi 119 at thev end of the stroke are seperated 'by the interrupterffinger 117. r1here being ii guarding potential at the first contact -whieh the y cuit is completedthrougrh the net 122, which extends terminal G?. of the hutterul through the private-wiper' of whatever iireftdieleetor` is occupying' the first' trunk of the second level in question, through thevhenk-multipilyinj` conductors to the contact-point ,with which the private-wiperiio luis.A engegeclf, `thence irough seid private-wiper 424, Winding` of the huck-releuseereliiv coiiductorf423, side-switcli-wiper 142, contact-point 152, conductors `ltiiind 41B` and private-muguet 122,2,to the non-grounded terminal of the `battery B1 andto ground Gil".L lie private-armature is ther 5y retained in its attracted ositioii even after'ithe einergriz`` ing circuit 1s bro enetr the .interigfupten the rotory-iiriiiutureffiiiger 120 returns to 4itsiiorinal position'in responseto tlie'letractiiig tei i iiioflthe .roe tary-armature? retriictingspringg' 113,` since; the eseapementltinger the nip erfforeinost 'escepeinent-tooth e si `e-switch-wiper.; 141v l'ieine, therefore,

eoi'ituct-point 15J., 'es soon iis the interrupter.-

t iitough the rotary-iimgiiet 10,8

` completed once more.` As

n result the i riitury-:iiimiture i'ii'ore step, and

the priveteliiifi( onto the y 5&5 is nio veci second i termine] of` th cond? level its normal position. Cleftrl private-wiper meets, e cir 'from `the groundetl giziiig Circuit i 55, conduct r gizing circuit rotated one offtlie privote-biiiik 51, .lSa'id econd Contact '126 also being grounded-the enel then, the shaft V will be rotated in a step-by-step manneras long as the private-Wiper continues to meet` with grounded-private-contacts. After having rotated onto the ninth contact, the private-wiper is rotated one more step and brought into engagement with the tenth contact of the second level of the private-bank; but, this last contact being devoidof guarding potential, as soon as the said wiper leaves the ninth Contact the magnetizing circuit that has up to this time maintained the prlvate-magnet energized is broken. This occurs at just about the time when the rotaryarmature at the end of its attractive or forward stroke, so that the private-armature v that has up to this time held the side-switch in itsI secondrposition, by the magnetizing force that has now disappeared from the private-magnet, falls back upon the rotaryarmature-inger and follows said finger as the rotary-armature returns to its normal position. Between the time that the privatearmature is released by the private-magnet and the time that the rotary-armature fully regains its normal position, the escapexnentfinger 138 which, during the rotation of the shaft, has been resting against the foremost tooth of the upper escapement-spring, disengages from said tooth and permits the side-switch to pass into the third osition. It is then that the side-sWitch-wiper 141 leaves the contactpoint 151 and passes onto the contact-point 155, and that the Wiper 142 passes onto the contact-point 156. The disengagement of the Wiper 141 and the contactpoint 151 occurs just before the interruptersprings 118 and 119 reengage, so that f the circuitl through the rotarymagnet is permanently broken in order that no further rotation of the shaft may take place' during its operation; and the engagement of the Wiper 142 avith contact-point 156 provides the private-wiper 55 with guarding potential.r The sideswitch-wipers 143 and 144 having/engaged with the contact-points 1,57 and 158, the subscribers line-conductors 402 and l.414 are extended through the 'respective wipers to the vertical and rotaryline-wipers 53 and 54 respectivelyi Said ifvipers being at the timefI in engagementwiththe tenth contact of thei, second levelof the line-bank.` the calling sub-ll! scriber is thiis placed in connection with repeater. Rl It may be stated at this pointill that it', after rthe subscriber has begun to", call, and before the first-selector has trunke ,A to the repeater, he should desire to discontinue his call he may interrupt the operation ofnthe first-selector aind restore it by simpl y, hanging up his receiiver on the svvitch-hooli` y 2. This may occur while the side-switch is either in the rst or second position, it matters, not. As a resultof restoring the recelv'er both sides of the main line will be grounded simultaneously. The vertical and rotary line-relays 69 and 70 will be magnetized at the same time, and, as a result following,.the release-magnet 98 of the firstselector will be energized and the first-selector will be restored. It has been described that in its action the release-carnarm 3, as it passes down when the receiver is restored, lleXes the release-springs 25, 26 and 27 into contact for a moment. Of these springs the release-springs 25 and 26 are connected, respectively, with the vertical and rotary line-conductors, while the third release-spring 27 is connected to ground G3. Therefore,-as a natural result, the temporary engagement. of these three springs sends a ground impulse overy each side of the main line, with the ei'ect upon the first-selector- ,line-relays already described. The current through the vertical-line-relay, during the release, passes from gronnd Gr3 throughv the ground-springs 24 and 23, conductor 400, release-springs 27, 2G and 2 5 to the'verticalline-conductor 402, and thence through said relay to` the non-giounded terminal of the battery B1 and to ground G1. Through the rotary-line-relay' 70 the current flows from the same ground Gr3 to the release-spring 27, thence through the release-spring 26 and to the rotary-line-conductor 414, thence through the line-relay in question to the non-grounded terminal of battery B1 and to ground G1. Since rthe contact-points 149 and 153 associat'ed with the vertical-sideswitch-Wiper 143 are connected together, and since the contact-points 150 and 154 of the rotarysi'de-switch-wiper 144 are connected together, it will be evident that. it makes no difference whether' the side-switch is in irst orsecond position, as the energizing' circuits during therelease, as pointed out in the conditions under consideration, will still be-the same. The fact is already familiar that when the rotary-line-relay is energized the private-magnet 122 is energized as a result, which latter during its energizatiou maintains the mivate-springs 127 and 128 in contact. It is also well understood that when the vertical-line-relay `is magnetized the private-spring 127 is connected with ground C* at the line-relay-springs. It was shown t at When said private-spring 127 was grohnded, and while in contact with the spri`g 126 the vertical-magnet 85 was energizeil; but in this case, since said springs 127 and 1126 are not in Contact, but instead the springs 127 and 128, a dii'erentcircuit is established that comprises the releasemagnet 98. The energizing current in this circuit passes from the ground Gr4 to the private-springs 127 and 128` thence through the release-magnet 98, conductors 411, 412, v413 and 408 to the non-grounded terminal of battery B1 and to ground G1. When the cam-arm 13 clears or disengages the releasesprings, the line-relays 69 and 70 then be- 11 Icome Clenergized` As n result, the rclease- `rent through the windings 21.8 and 2.19 of magnet 98 becomes dencrgizcd und the nrthc differential-relay puisses through Suid mature of the lutter in regaining its normal coils in usuch n direction thut the Suid `difa position restores thelirstselector-switch in ferentinl-rcliiy doei,l notbecomc energizedg- #known'manncn It should be made hut the verticul-line-relay 200 does, uudthe 70 `ceerftlmt'when the first-selector-shuft is lutter attracts its armature 202. The ,enr first operated, and 'when thc off-normal gugemont of thc'sprngs 221 und 223 duringy :trical Contact with the time that the diflerentiulfreluy-springs guarding` potentiul `211 und 212 nrc in contact not only providesl i z ie conimctor-privutethe culling suh-stntion with talkin battery an -oontacts, through the so-cnlled private- 75 l current, but also causes therotary inercia `normal-conductor '426, to corres )on with 201`to become energized'in series with the thenumber ut the sub-station #17000. .The resistunce-coill 220, hy` reason of pal-tof the estublishmetof `thisguarding potentiel is tu :ing eunent heilig diverted through stud` y renting any calling 1otery-inerelaynfter it leaves "thevconducso y iugconncctionwith tor 429,` `whichf current` the ,over theinormal-line-condu n. passes to `the nonj-g1'o1.|r idcd terminal of buttery Bwundto' i SQtlmttermiuutc kin the' con 'ground (il. Butr the energized condition yhilethe said line ismuking" of :saidvertical und tl when. the shaft falls to its "i `no significunce ut present.` The'culling'sub- '85 onw`hen the switchis releusedny sci-ibex' now, it will be "this guurdihgipotentiul ris then destroyed ut the instant "i that `the vnormalfpost-urm,63 i oroesnpert theisprings 68 rund 66. How-y with talk l y ever," since-the culling subscriber continues sl moved from the 9o tomakehi he continues to operate his iA it normally enobtain the desired connecgages. But the rotery-linc`reluy is not dc- Atten `will be culled tothe fuct energized, us will be pointed out, until the x i established ut vertical-line-conductor, is iifgrounded.` The rj`5 und, therefore,` ut the subscriber after ha yo `thesecond level of the pri button 29 twice und the vate-twill:/51\,k f rees a cur nt through the continues by pressing the* relay 222 ofthe )cuter R, which signin four times. gain the vertical-linemature closes u conductor 402 is momentarily grounded four ling station with times. The rst-selector-linelreluys 69 und 100 c primurycircuit 70 inving been out oil'` from the line at the u The current that instant that its side-switch passedint'o third energizes there y 222 p from grou'l'id e line `being connected then- I, G' totheside-switch-wi throng-l1 the with the repeater R, thegrounding of the release relay 811 ol'idu'ctor424,private vertical -line `cofmluctorthenenerguzes the 105 i-ctmductor 425, anx-- line-relay 200 und the differential-relay 209` lthe;non-groundcd telrmiof the repeater R. T e current in this onse f undr to grolind (il. The .lifter reaching the v j r 'n"1u.ture233 und tl f l' 221 r und thctir.l gh the contuct-` 110 223into contnctittwvlnch' e, hns been point 157, the stated, the culling "sub-stut( is lnfovidcd 1iercntniI-line-reluy 218;" with tnlkingrhnttery current. The current conductor `430,` vertical line-relay 200,'con passes' from round (.i't und through the doctor 431 tothe non-groundedter inul of clicrentinlu'e ity-spriu' 2 und 21Il` buttery B1 and to groundy GH `Euchtime 115 through the auxiliarl 221, that the.verticul-line-reluyf200is energized resistance-coil." 220, thespring 204 is yforced'onto'tl'ie s 219, trunk-conductor 422 he# lrstfselector F1 line-conductor itl n current that energ o the'talking a parat pring 205.y` und since the differential-willy-forces'ut'thc- ,co1 f .i rosuine time the spring 212 :onto i' duc-tor 432 is i ygrounding' `tl `145'."` wup i, .v f w yI-l' will b conductor 4502 tact-po 7 hn condui. r e tial-relay 20 yconductor 431 to tl hfl' ground G to the .yf-200, 212 and 21.3, linerfluyspring'svv 205, andf204 I groundedtcrminul fu-.omluc-.tor 43310 the tof battery B1 und to ground G1. The curtrunk-conductor e 7.132.1 he effect grounding tl' ie vertical-line- 130 llo . lenergized v conductor 402 produces,

.throu gh which as was stated, a. deenergization of the rotary-line-relay 201, indirectly. The energizin circuit through said relay when the vaulii iary-relay-springs 223 and 221 are closed comprises the differential-relay-sprin s 211 and 212. Therefore, since the di erential-relay isenergized when the vertical-line-conductor is grounded, the springs 212 and 211 are separated, destroying the ma netizing current throu h the said rotary-line-relay 201.' The Vsu scriber, after operating the push-button 29, operates the push-button 30 once, grounding the rotary-lme-conductor 414 once. The first effect of grounding the said line-conductor becomes manifest in the energization of the diferentialrelay 209, which latter produces a shifting of the energizing circuit that maintains the rotary-line-relay 201 energized. The current, instead of passing through the said rotary-line-relay fromthe ground G lnow passes vhrough said relay from the ground Grs at the said sub-station, the latter ground being substitutedV for the former at the instant that the .differentialline-relay-springs 211 and 212 disengage. The energizing current that passes through this diterential-relay and through the ro-y tary-line-relay 201 enters the' circuit at ground G3 and passes to the rotary-line-conductor 414, after reachingv which it extends through the side-sWitch-wiper 144, wiper 54, rotary-trunk-conductor 422, differential-relay-winding 219, conductor 429, rotary-linerelay 201 to the nongrounded terminal of battery B1 and to ground G1. At the instant that the ground connection to the rotarylitre-conductor 414 is interrupted, both the differential and rotary linerelays then become denergized, but the rotary-line-relay becomes renergized at once as soon as the ditferential-relay-armature 210 advances suficiently to permit the differential-relaysprings 211 and 212 to rengage. Since the line-relay-springs' 205 and tained in connection while the differentialrelay-armature 210 is attracted, and, therefore, when the differential-relay-springs 212 and 213 and the differential-relay-springs 214 and 215 are forced into contact, the inter-exchange rotary-trunk-conductor 434 is grounded, but since the differential-relay is only. once the said trunk-conductor is only tounded once. The; path the said conductor 434 extends from ground GS through the springs 212 and 213 and through the line-relay-sprugs 205 and 206, difl'erential-relay-springs 215 and 214, conductor 435 to the rotary-trunk-conductor 434. The 'eect ot ounding said conductor 1 lwill, be considgelred hereinafter. f course, as long the verticaland rotary linef relays 200 and 201 are maintained energized together the line-relay-springs 204, 205 and 206 are mainthe ground impulse reachesbut plays a very important part during the The sub-'sta-v release, as Will be made clear. tion #7000 being connected directlywith the repeater at this point, it follows that it the calling operator restores his receiver to its hook and grounds, simultaneously, the vertical and rotar line-,conductors 402 and 414, he will there y restore the centralaparatus throughthe repeater. The ground-` ing of the vertical-line-conductor 402 maintains vthe vertical-line-relay 200 energized, and causes a flow of current through the winding 218 of the differential-relay, but the grounding; of the rotary-line-relay shunts the winding 219 of the differentialrelay out of service, causing the current to cease fiowing through said coil and producing at once, of course, as a result, the energization of the differential-relay, due to the magnetizing effect of the coil 218. The Shunted circuit in which the coil 219 is cut out of service may be traced from round G3 to the rotary-line-conductor 414 t rough the Winding 219 of the di'erentialrelay to the conductor 429, resistance-coil 220 to the ground terminal G5. As soon as the differentialrelay becomes energized and the differential-relay-springs 211 and are forced apart the shunt across the winding 219 is removed, at which instant a current then Hows through said Winding'in series with the iotarylinerelay 201, the said rotary-line-relay remaining energized and the differential-relay being strengthened. The current through the winding 219 andV the relay 201, of' course, extends fromV ground G3 through the said coils 219 and 201 to the non-grounded terminal of battery B1 and to round G1. The trunk-release-springs 207 and 208 being connected, since both line-relays are maguetized, it follows that as soon as the differential-relay-springs 216 and 217 come into engagement the back-release-relay 81 of the first-selector Flbecomes energized by current flowing from ground G" through the side-switch-Wiper 142 of the irst-selecf tor F1, through the said relay 81 to the private-wiper 55, trunk-release-conductor 425, trunk-release-springs 208 and 207, differential-relay-springs 217 and 216, resistancecoil 232, conductor 431 to the non-grounded terminal of battery-B1 and to ground G1. As soon as the back-release-relay attracts its armature 82 the releasemagnet 98 is energized. The current that energizes the release-magnet Hows from ground' through the back-releaserelaysprings 83 the non-grounded t gizng current .passes 'through the springs ease of the second-sclector also.

the private-contact with which it is, connected, in order that no other trunk-seeking second-selector may be able to seize upon the trunk-conductors 463 and 464. The secondselector S may b e released like the first-selector, while its side-switch isin first or second position, if the inter-exchan e trunkconductors 432 and 434 are roun ed simultaneously vfor a moment. he release will occur if the calling subscriber hangs up his receiver at any stage of'the call that may find the second-selector-sfle-switch in. its first or second position. It will be clear that if the vertical and rotary line-conductors 402 and 414 are ygrounded simultane-v ously for a moment, while the first-selector,

repeater and the second-selector are connected, and while the second-selector-side-switch is in either the {irst or second position, the first-selector will be released as describedthrough the repeatcr-during whichrelease the trunk-conductors 432 and 434 will be rounded simultaneously, producing the re- The simultaneous grounding of the inter-exchange vtrunk-conductors Vproduces the simultaneous' magnetization of the second-selector vertical and rotary line-relays 165'and 178, by which operation the release-magnet 191 becomes magnetized. As soon as lthe line-relays are denergized the restoratiqnof the secondselector follows, as usual; 'fter the subscribers line-conductors an extended lto the connector the operation o f the calling device atthe'calling -stationwill operate the connector. The rounding of the verticalline-conductor wil cause the vertical-linerelay 200 and the differential-relay 209 at the repeater R to be energized twice. As a result the vertical-trimk-conductr 432 becomes grounded twice and the vertical-linerelay 318 of the connector becomes energized twice by a-current flowing from ground G" at the repeater R,- tothe vertiralrunk-conductor 482, thence through the si le-switchld wiper 166 to the contact-point 192, conductor 466, ivertical-line-wiper 174, vertical` ltrunk-conductor 463, vertcal-line-relay 318 of the connector C, conductors 467, 468, 469, 470 and 471 to the Anon-grounded terminalv of battery B and to ground G". 'The vertical-line-relay then attracts its armature 319 and closes thc springs A320 and 321 into contact, .establishing an energizing circuit through' the vertical-magnet 261. The enerfrom ground G" 321 and 320, conductor 472, private-springs 291 and 290, conductor 473, side-switch-wipcr 302, contact-point 306, conductor 474, vertical-magnet 261, conductor 468 to. the non-grounded terminal of battery B and to ground G. The vertical- "magnet, upon attracting its armature twice,

raises the shaft 252 two steps, in the same manner that the previous selectors have op- -groun s 'tary-magnet 277 instead minal of battery B' and to ground ergizcd once, the said relay in turn producerated their shafts, and places the eonnector-wipers 253, 254 and 255 oppositevthe first contacts of the second level of their'corresponding banks. The calling subscriber then resses the rotary-buttonj 30 ,oxxcefro the rotary-line-conductor '414 once, y' energizes the rotary-line-relay`201 and, the

differential-relay 209 of the re '1,

which former in turn groun s i L, trunk-conductor 434 once. The said conductor extendn to the connectorv causes the the current in lthialast. circuit flowing from.' v ground G to the rotary-trnk-conductor 484" 1j, and through the second-selector-side-switchwiper 179, contact-point 177, conductor 475,?v f rotary-line-wiper 175, trunk-conductor 464,; rotary-li'ne-relay 324, conductor" 46T to,` the', non-grounded terminal of batter? B'. and f 'i to ground G. The connectorine-relay,- '85 springs 321 and 326 `being brought'. together, the private-magnet 281 is then energized b a current flowing 4from ground Glthroug said springs 321 and-326,- conducto'rf478, pri-ff vate-magnet 281, conduction-17,14 to the non-f" groundec .terminalof battery BHaudV to, ground G. The connector-private-mzsignet,'i`` bein'g ener `zed once, attracts its armature once, whic permits the' connector-sideswitch to pass to second position, the sde- 9a switch-wiper i302'passingA from the contactg f f point 306 onto the contact-point 307,' ar`id-` the side-switch-wiper 303 from contact-1 point 309 onto the contact-pointi310,l flhefl, shifting of the side-switch-wi 'efr 302 pr 'f109 duces a change in circuits in t e connector, so that when the ,vertical-button; 29`v is pressed ten times for thelast digit the 261 'ed vertici y` i magnet ,is operat enjt espr'f" v, 320 and 321 are brought'into contact. time the springs 320 and,321 to ,thefk a circuit '1s established Ircam` unl-Gril through the sprngs 321 an j, 320i-,1an through the private-sp'ings 291;,and- ,290.40 1 i) the sde-switch-wiper 4 02 assing,througllxlf` which latter it extends to'A e contact-point 307,*the conductor 480 `thence through the., rotary-magnet 277 to thernon-grolinded'te eachV electrical pulsation in this cirmiitthe' 1., rotary-magnet attracts its armature 278, tating the shaft 252 one step at a time, slid` ing the wipers 253 and 254falong thesecond level of the banks whichftlijey lengager/At' the end of. the tenth puls-ation' the wipers are moved onto the tenth contact-terminal-iofthe Ji secondlevel of theirbanks, .Then for the laatA ytime the rotary-button 30wis ed.; once, and lasa result the rotary-tru v-conductor 434 is grounded atthe .repeater ,R once by the method describedr- Again the rotary-line-relay 324 of the connector ieening un operation of theprivate-magnet 281 18u positionwitl'r thc n guarding own linenty the]connector-privateflmnk-com 5 tects `rthatg"correspond tothe sub-station l that the that prmits the s l .'-l1)3,^304 and' 305 in connection 'with tl tact-points 308, 311,314 erul`317, res tivcly. The engagem wiper 303 with the oton 255,k and' at kt 'und254, d, threfo n non. #2420; The yculling firstfsolector, it `will bercmernbored, pinces n guarding vpotentiel over its #7 000, :it thc instant, that the olf-normal# spring;` 6" comes @into `gromuled swing 08.` Later, and et the in? etnnt that tllc connector es on the `culled si scribers normnl-comlut the calling connector' `plucrs u glurding liotentiulover the called l` nt thefinst'eut liz-switc'll-ivipel" 303 engages with their-omelet mint 3l\l. lvidently, then, u. linel is protected by :l guarding otentinl eitherqvlien culling or when culle( -in theforuicr cnseby operations in the first-selector, und in the lutter onse by `the connector.`

l Thc eshlblishnwnt. of the guarding potentiel over the celled line #2420 not only rotects it from further seizure, but also.y orcos :l y current through the lritlire-eutfofleluy 350 of the called lirstsrleetr r FQin order thin:` thelettrr through fits nrlunturemuy" septir through the jverticnl und `rotary lincfrelnys l 3F14` und 355,. `tlu1t 'nornullly extends ncross `t hc l ine-condnomi-$5483 .untl '484, undy n't "the sumo time interrul'its "si connection .between ed terrninnlof'the'lbaittery B,`fwliichy terini# `nel is" directly connectedv with'th'e spring 353Tv Since the conductors'483`nnd 484 are indllldhoneonleech side/of the "muin telking circuit, us` lwillbe herenftcr disclosed, it

itchto pass to third ff' -'switch-n'il'xers .y 302,

t` of the sidcswitchhot-point 31L 'pinces 't the private-wiwi' lewtcnth` private-contact of the, `secondlevel ofthe privatcLbnnk 25.1, so yes t0 preclude any other connector from esl Partyris'then'in a posi y station by meltnsoffh yith thcl normui-4 conduetors48l und 4 821tlmt1 constitute, the `terlnirmls of` the `culled sn the ysubfsteton #2420,

contnct "with the f "vate-normal-condnctor 4.86.'l At `circuit through `the rclcnsoanngnet `connector when'the arunltnre ofrth 4,into contact. :The cnergi l the` releasing-'magnet all "How from the` m'mmded"y y rent supplicdto the called sub`sta\tion,'in l n order that no, undesirable `interruptions 'ma take place thereby. The'energizmg circuit through the b|'idge-cntolrelhy 350 extends` from -ground G to the connector-sideswitch-contluct-point 311,` side-switch-wiper 303, conductory 485privatc-wipei' vr255,1'pri-1 1 vatelnomml-condnctor 480, sprin 356, contact-pointv 357, "conductor 487, `rid`gecut` ofreley-30to the non-grounded'terminai of lbnttcry `B" and to ground GI l `The 'connection between thiefcalling'"und,cltlltfly i line having been estblisllod,l the cilill l t 5 l L has beencnlled by anothrco'nn ,"ftl'l'o're willv be a; guarding potential at. the tenth pri `vate-contact of the secondflovelj of t vate-bnnk251, corresponding t r hand, im., erst-semm-Hrsof is being used,land the shaft ofk l tor is offunormalasfa roslilqthc same privato# bank-contact will be `connectd to ground from the instant that thehormnlpost-arm" 3.58 permits the otinormhl-sbjpring'y lto'ngege with thc grounded'contactint. Suid gllmrdinp; potential` will `thorn'i vnte benk of tho connecten'4 by `w o because thc cncrgzntion the priv net tlasa final resllltof grounding l tary-line-conductorAl-t sets up nnonergi ng witze-magnet forces the" tery tothcftcnth col y l `level of, the 'connector-private han through they private-,wipcry 255 "485', sido-s `Itch-wi'per 300 A'conteo conductor 48B, primi i md conductors-489 and ,0, rolea 205, conductor 491 to tho nongr d minal of battery Bf erudito giron connector-,miense-megnot the rclense-urnmturc 266n1oves the dog 268 so that thvl lng V274 is caught and h hldN in the oper-tore 27,6 on tho end of th."

,its

link. Of course, when the double-dog is thus rotated, the locking-arm 272 is then withdrawn from the longitudinal teeth 257. Then the shaft is free to rotate back to its normal rotary position, by reason of the tension of the coiled spring 260, until the normal-post-arm 25,9 343. At that instant the shaft-support 342 enters the slot 343", and the said shaft of. necessity falls'to its normal position. The release-armature, when it rotates the doubledog-268, at the same time drives the sideswitch toits first position, about the pivots of the latter, by means of the side-switchlink 301 and the release-arm 273. The latter, by vpressing the-former back forces the escapcment-finger 295 back between the escapement-springs 283 and 284, which finger 295 1s then caught behind the rearmost lower tooth 287 where it remains until the connector comes into use again.Y The Vrestoration of the connector-shaft begins while the releasemagnet 265 is'in an energized state; but since f the energizing circuit through said ma et rect communication (if, through which the busy signaling curren ratus, such, for example, as

comprises the private-wiper 255 and the sideswitch-wiper 303, it will 'be evident that as soon 'as the shaft'begins to rotate to its norma1 `position the energizing circuit through the release-magnet265 will be broken as soon as thesaid prlvat-wip'er 255 leaves the private'f'contact-point with which it has been f en -V; and ythe same energizing circuit is alsointerrupted at'the 'side-switch-wiper 303 when the latter is forced into its first posiestablished connection, presses the signalingbutton 12at/his sub-station, with the retion. lThe s'ubscriberthen-thinking he has sult that/th `spring 11 is separated froml ,the contact' point 10 and closed in con- 'nection/ with the grounded contact-point 35. -The ,saidA sprmg 11 lbeing in diconducto ,402, through the primary-springs 13 and 1 through the contactpoint 31 and spring 33, vit follows that the pressing of the button 12 grounds the Vertical side of the line. The grounding ofthe vertical line causes the energizingof thefconnector-'vertical-line-relaJp-Bl in theusual manner, and since the vvconnector-side-switch4 is in rst position,` ve connector-vertical-magnet 261 is energized when the line-relay-springs 320 and 321 are pressed'into contact through a circuit that is already' familiar. As a result, and for, .reasons previously described, the shaft of ,jthe' connector is raised and the `springs 341 and 340'which it controls. vare brought into contact. `The engagement' o'f these two" arts completes a busy cir l .it 1s transmitted to the calling sub-station, whl'ch current may originate in any suitable appathat represented comprisei a coil 343 in at1F,'Fig". 2, which current is induced. The

' which the Said busy strikes the normal-post ,.Xwiper 166, conductor 466,

means? subscriber, having been instructed, will f understand from this signal'that the line he desires is busy. This busy current passes from the coil 3,43 to the conductor 492, through the spiings 341 and 340, conductor 493, contactdenser 345, conductor 464, wiper 175, conductor 475, side-switch-wiper 179, trunk-com ductor 434, winding"229 of the repeatingcoil 225, condenser 231, windin 2 27 of the repeating-coil 224, trunk-con uctorv 432, l wiper 174, trunkconductor A63, vertical-line-relay 318, back \to the coil"3 4$.'. Thiscurrent is then iniuced inturn inltherepeater-cols 228 and 226 whenceuit pisses to the line-conductors 414 and 402,'and through the primary winding 7, from which-latter it passes to the seconder).1 coil 17 and to the receiver 16. The

subscriber will then restore his receiver to its switch-hook, thereby groundin both the linefconductors 402 and 414, as

scribed.4 The grounding of these two con-y dctors causes a simultaneous energizing of the rotary and vertical line-relays 324 and 318 ofthe connector, which relays, attracting their armatures 325 and 319 simultaneously, permit the connector-trunk-releases rings 322 and 323 to come into contact.

he engagement of said release-springs point 315, side-switch-wiper 305, springs '329' and 328, conductor 494, con-A fore deestablishes an energizing circuit through the connector-release-magnet 265, and through the second-selector-backrelease-relay 187, in

lease-magnet 265, conductor 491 to the nongrounded terminal of battery B' and to ground G. The release-magnet of the connector and back-release-relayf; of the second- 'selector S becoming energized, it will be vi dent that both the connector and the seconds elector will be/rleased in a familiar manner. Furthermore, the first-selector F1 will a1so.be released in away that hasalso been pointed out. But ithas been described that the calling subscriber did not find the line #2420 busy, and that he did complete his connection with said line. After so doing he presses his signaling-button 12 in the manner already stated, and thereby grounds the vertical-hnsconductor 402. ,The grounding of said conductor energizes the` vertical-line 'relay 318 by means and circuits already familiar. `Since the side-switch of the con#v Y mont with the contact-point 308,- the cngagcment of "the linerelaysprings 320 and 321 energizes theconnector-ringer-relay 326. The 

